Electromagnetic switching devices



July 5, 1966 w s 3,259,810

ELECTROMAGNETIC SWITCHING DEVICES Filed NOV. 27, 1963 INVENTOR.

19- %0eW/a%%'//mm 4 7 BY United States Patent 3,259,810 ELECTRGMAGNETICSWITCHING DEVICES Robert A. Williams, Fort Worth, Tex., assignor toTalon, Inca, Meadville, Pa. Filed Nov. 27, 1963, Ser. No. 326,633 4Claims. (Cl. 317172) This invention relates to electromagnetic switchingdevices. The invention is applicable to various types of switchingdevices wherein an armature is driven by electromagnetic action and thearmature or devices carried by it perform contact making or breakingfunctions in an electrical circuit or circuits. The invention isparticularly applicable to devices wherein the contact making orbreaking functions are performed quite rapidly and continuously, forexample, a D.C.A.C. chopper. Further, the invention is especiallyapplicable to miniaturized devices wherein it is desirable to achievehigh performance characteristics with very limited available input powerand space.

The general object of my invention is to provide improvedelectromagnetic switching devices of the types above-mentioned.

Another object is to provide such improved switching devices which whenminiaturized will provide normal operation even in an environment wherethey are subjected to heavy shock and vibration.

Another object is to provide such improved switching devices whichutilize available input power so effectively as to achieve highperformance characteristics even when made in very small sizes.

These and other objects are effected by my invention as will be apparentfrom the following description taken in accordance with the accompanyingdrawing, forming a part of this application, in which:

FIG. 1 is a schematic longitudinal section view of an electromagneticswitching device in accordance with a preferred embodiment of myinvention;

FIG. 2 is a plan view of the device of FIG. 1;

FIG. 3 is an end elevational view of the device of FIG. 1; and

FIGS. 4 and 5 are respectively fragmentary end elevational and planviews illustrating one type of switching arrangement that may beutilized with the device of FIG. 1.

Referring now to the drawing, there is shown an electromagneticswitching device including a drive coil assembly 11, upper and lowerpermanent magnet bars 13, 15, a. left end piece 17, a right end piece19, and an armature assembly 21.

The armature assembly 21 includes an armature 23 shown as a tubularmember made of magnetic material. Disposed within and fixed to thearmature adjacent its right end portion is a disk 25 of non-magneticinsulating material. Supported by and fixed to the disk 25 and disposedcoaxially of the armature and extending outwardly therefrom is a rod orreed 27 which may carry a contact or contacts to perform contact makingand breaking functions as will be hereinafter explained. The armature 23is mounted on pivots 28 for pivoting about the transverse axis indicatedby the at 29 in FIG. 1.

The coil assembly 11 includes a spool 31 of non-magnetic material uponwhich a winding 33 is disposed, the winding being provided with inputleads 35 to be connected to a suitable power source (not shown). The

spool 31 is fixed by any suitable means, such as indicated by anglebrackets 37 in FIG. 1, so that the spool bore 39 is coaxial with thearmature 23 when the latter is in its neutral position. Thus, the coil33 is so disposed relative to the armature 23 that alternate north andsouth poles (indicated in FIG. 1 by N-S and S-N) will be created at thearmature left and right end portions when the coil 33 is energized by asuitable alternating current power source.

The left end piece 17 is a disk of magnetic material having acylindrical protrusion 41 extending inwardly therefrom and coaxial withthe spool bore 39, and with the protrusion 41 extending within thearmature left end portion; the cylinder diameter being slightly lessthan the adjacent armature portion inside diameter, so as to provideoperating clearance.

The right end piece 19 is a disk of magnetic material having a centralbore 43 surrounding the armature right end portion, the diameter of thiscentral bore being slightly greater than the outer diameter of theadjacent armature portion so as to provide operating clearance.

The left and right end pieces 17, 19 are held in fixed spaced relationby the permanent magnet bars 13, 15, which are received at theirrespective end portions by respective slots 45 in the end pieces.

The permanent magnet bars 13, 15, as shown by FIG.

1 are arranged so that their ends are oppositely poled.

As shown, the left end portion of the upper permanent magnet bar 13 is asouth pole, while the left end of the lower permanent magnet bar 15 is anorth pole. Now as a practical matter, the armature 23 is always ineither its clockwise or its counterclockwise position, or is in motiontoward one of these positions. When in the clockwise position, the lowerleft armature end portion is abutting the lower portion of the left endpiece protrusion 41 while the armature lower right end portion isabutting the lower portion of the right end piece bore 43. When in thecounterclockwise position, the armature upper left end portion isabutting the upper portion of the left end piece protrusion 41 while thearmature upper right end portion is abutting the upper portion of theright end piece bore 43' Now the left and right end pieces 17, 19 aremade magnetically integral with the permanent magnet bars 13, 15, sothat there is no gap or disruption of the magnetic circuits at thejunctures of same. When the armature 23 is in the theoretical neutralposition (coaxial with the coil spool bore 39) the magnetic effects ofthe permanent magnet bars 13, 15 are theoretically equal and oppositeand therefore cancel out. It is important, however, to understand thatwhen the armature 23 is at or near one of its terminal positions(clockwise or counterclockwise) the magnetic effects of one permanentmagnet bar are predominant and the effects of the other can forpractical purposes be ignored. This means that when the armature is ator near its clockwise position the lower permanet magnet bar 15 ispredominant and there is a magnetic circuit extending around a loopincluding the lower permanent magnet bar 15, the lower portions of theend pieces 17, 19, and the armature 23, with the permanent magnetpolarity of north at the left end adjacent the armature and south at heright end adjacent the armature. When the armature 23 is in itscounterclockwise position, the situation is reversed, with the upperpermanet magnet 13 then predominant and the permanent magnet polarity ofsouth at the left end adjacent the armature and north at the right endadjacent the armature. As hereinbefore stated, when the coil 33 isenergized from an alternating current power source north and southmagnetic poles are alternately established at the end portions of thearmature 23,

In operation, assume that the armature 23 is at rest in its clockwiseposition. Then assume that the coil 33 is energized from an alternatingcurrent source and at a given instant a north pole is established by thecoil at the left end port-ion of the armature 23 while a south pole isestablished at its right end portion. These poles will be instantlyrepelled by the adjacent permanent magnet poles so that the armature 23moves toward the counterclockwise position. As the armature approachesthe counterclockwise position, it will be attracted by the adjacentpermanent magnet poles. Thus the armature 23 is both pushed and pulledfrom the clockwise to the counterclockwise position.

Then on the next half cycle of the alternating current coil energizingsource, the polarity of the armature ends will reverse so that the leftend is now a south pole and the right end a north pole. The armature 23will then be repelled by the adjacent permanent magnet poles and willthen move toward the clockwise position. As the armature 23 approachesthe clockwise position, it will be attracted by the adjacent permanentmagnet poles. Thus, the armature is both pushed and pulled from thecounterclockwise to the clockwise position. This process is repeated atthe frequency of the alternating current coil energizing source.

The effect of the above-described structure and arrangement isadvantageous in several respects. It results in a positive snap-likeaction of the armature 23 in its movement from one position to another.This armature action of course also becomes the characteristic of theswitching or contact element or elements that are carried by thearmature. Thus, the tendency to contact bounce is effectively resisted,and normal operation persists even in environments involving heavy shockand/ or severe vibration. Furthermore, the above-described structure andarrangement achieves very effective utilization of available power inminimum space and is consequently admirably suited to miniaturizationtechniques.

It should be apparent from a careful consideration of the foregoing thatin essence, the structure and arrangement of the present inventioncontemplates the following: Providing means for producing a first set ofmagnetic poles having alternately a first and a second polarity atspaced locations on opposite sides of the pivot on a pivoted structure(for example an armature), permanent magnet means producing a second setof predominant poles adjacent said first set when said pivoted structureis in a first terminal position and while said first set has said firstpolarity (clockwise or counterclockwise) said second set of poles beingof polarity such as to produce a first repelling force couple on saidpivoted structure tending to push said structure toward its secondterminal position (counterclockwise or clockwise), permanent magnetmeans for producing a third set of predominant poles adjacent said firstset as said pivoted structure approaches said second terminal position,said third set of poles being of polarity such as to produce a firstattracting force couple on said pivoted structure (while said first setstill has said first polarity) tending to pull said structure towardsaid second terminal position so that when said first set of polesassumes its second polarity a repelling force couple will be produced topush said pivoted structure back toward its first terminal position andas it approaches same an attracting force couple will act to pull sametoward said first terminal position, the cycle being repeated at thefrequency of the cycle of change of polarity of said first set of poles.

In the preferred embodiments of the invention, the said first set ofpoles having alternately a first and a second polarity is produced bymeans of a suitably disposed winding or coil energized from analternating current power source and the second and third sets ofpredominant poles are produced by oppositely poled permanent magnets.Further, in accordance with preferred embodiments of the invention thepoles at one end portion of the permanent magnet structures are disposedon opposite sides of and exteriorly of said pivoted structure and thepoles at the other end portion of the permanent magnet structures aredisposed on opposite sides of and interiorly of said pivoted structure.

It is apparent that the details of structure of devices embodying theprinciples of my invention may take many different forms. Further,details of structure such as various armature pivot mounts, drive coilmounts, switch ing element configurations, frame structures,encapsulating techniques, and the like, belong to the prior art and aretherefore not labored herein. For such details of some electromagneticswitching devices of the general type to which the present invention isapplicable, reference is made to my United States Patent Numbers2,959,648 and 3,172,975.

For completeness, one form of switching element which may be utilized ina device embodying the principles of my invention is shown by FIGS. 4and 5. There, a conductive contact shorting element 47 is fixed to therod or reed 27 which is in turn carried by the armature 23. The shortingelement 47 acts to bridge between the contacts 49, 51, thereby openingand closing the electric circuit containing the contacts 43, 51 at thefrequency at which the armature 23 is driven.

The foregoing disclosure and the showings made in the drawing are merelyillustrative of the principles of this invention and are not to beinterpreted in a limiting sense.

I claim:

1. An electromagnetic switching device comprising:

(a) a pivoted structure mounted for oscillatory pivoting movement abouta pivot axis;

(b) means for producing a first set of magnetic poles having alternatelya first and a second polarity at spaced locations on opposite sides ofsaid pivot axis;

(c) permanent magnet means producing a second set of predominant polesadjacent said first set when said pivoted structure is in a firstterminal position and while said first set has said first polarity, saidsecond set of poles being of polarity such as to produce a firstrepelling force couple on said pivoted structure tending to push saidstructure toward a second terminal position;

(d) permanent magnet means producing a third set of predominant polesadjacent said first set as said pivoted structure approaches said secondterminal position, said third set of poles being of polarity such as toproduce a first attracting force couple on said pivoted structure whilesaid first set still has said first polarity, said attracting forcecouple tending to pull said pivoted structure toward said secondterminal position;

(e) so that when said first set of poles assumes its second polarity arepelling force couple is produced to push said pivoted structure backtoward said first terminal position and as it approaches same anattracting force couple acts to pull same toward said first terminalposition, with the cycle being repeated at the frequency of the cycle ofcharge of polarity of said first set of poles.

2.. The invention in accordance with claim ll, wherein said first set ofpoles is produced by a coil to be energized from an alternating currentpower source and said second and third sets of poles are produced byoppositely poled permanent magnet structures.

3. The invention in accordance with claim ll, wherein said second andthird sets of poles are produced by oppositely poled permanent magnetstructures and the -to actuate a separate control device atsubstantially the 10 poles at one end portion of the permanent magnetstruc- References Cited by the Examiner tures are disposed on oppositesides of an exteriorly of UNITED STATES PATENTS said pivoted structureand the poles at the other end portion of the permanent magnetstructures are disposed On 3,177,412 4/1965 Carlson 317173 oppositesides of and interiorly of said pivoted structure. 5

4. The invention in accordance with claim 2 which OTHER REFERENCESincludes means operatively connected to said pivoted Perret, GermanApplication No. 1,066,658, published structure for movement through agiven are in response Oct. 8, 1959.

to the oscillatory movement of said structure, said means BERNARD AGILHE ANY Primary Examiner same frequency as said alternating currentpower source. HARRIS, Assistant Examiner-

1. AN ELECTROMAGNETIC SWITCHING DEVICE COMPRISING: (A) A PIVOTEDSTRUCTURE MOUNTED FOR OSCILLATORY PIVOTING MOVEMENT ABOUT A PIVOT AXIS;(B) MEANS FOR PRODUCING A FIRST SET OF MAGNETIC POLES HAVING ALTERNATELYA FIRST AND SECOND POLARITY AT SPACED LOCATIONS ON OPPOSITE SIDES OFSAID PIVOT AXIS; (C) PERMANENT MAGNET MEANS PRODUCING A SECOND SET OFPREDOMINANT POLES ADJACENT SAID FIRST SET WHEN SAID PIVOTED STRUCTURE ISIN A FIRST TERMINAL POSITION AND WHILE SAID FIRST SET HAS SAID FIRSTPOLARITY, SAID SECOND SET OF POLES BEING OF POLARITY SUCH AS TO PRODUCEA FIRST REPELLING FORCE COUPLE ON SAID PIVOTED STRUCTURE TENDING TO PUSHSAID STRUCTURE TOWARD A SECOND TERMINAL POSITION; (D) PERMANENT MAGNETMEANS PRODUCING A THIRD SET OF PREDOMINANT POLES ADJACENT SAID FIRST SETAS SAID PIVOTED STRUCTURE APPROACHES SAID SECOND TERMINAL POSITION, SAIDTHIRD SET OF POLES BEING OF POLARITY